...DISCUSSION... MODELS HAVE CONVERGED ON SOLUTION THAT AN UPPER TROUGH FORECAST TO AMPLIFY OVER THE WRN STATES WILL MOVE INTO THE NRN PLAINS DAY 4 /FRIDAY/ WITH DOWNSTREAM RIDGING FROM THE UPPER MS VALLEY INTO THE GREAT LAKES. QUASI-STATIONARY FRONT WILL REMAIN FROM THE OH VALLEY WWD INTO THE CNTRL PLAINS. SOME THREAT FOR A FEW SEVERE STORMS MAY PERSIST IN VICINITY OF THIS BOUNDARY GIVEN MODERATE TO STRONG INSTABILITY EXPECTED IN THE WARM SECTOR...ESPECIALLY FROM THE CNTRL PLAINS INTO THE MID MS VALLEY REGION. HOWEVER...IT APPEARS THE STRONGER WINDS ALOFT WILL REMAIN IN COOL SECTOR...AND TOO MUCH UNCERTAINTY EXISTS REGARDING HOW ONGOING CONVECTION WILL MODULATE WHERE A HIGHER COVERAGE SEVERE THREAT MAY EVOLVE.

IMPULSE EMBEDDED WITHIN THIS TROUGH IS FORECAST TO EJECT INTO SRN QUEBEC BY DAY 6 WITH REMAINING PORTIONS OF THE POSITIVELY TILTED TROUGH GRADUALLY SHIFTING SEWD. THIS WILL FORCE WRN PORTION OF THE FRONT TO ADVANCE SEWD THROUGH THE PLAINS AND MID MS VALLEY. SEVERE POTENTIAL WILL LIKELY PERSIST AS THIS BOUNDARY INTERACTS WITH THE UNSTABLE WARM SECTOR. HOWEVER...IT APPEARS THE STRONGER FORCING FOR DEEP ASCENT WILL LAG THE SFC FRONT WHICH INCREASES UNCERTAINTY REGARDING THE EXTENT OF STORM COVERAGE GIVEN LIKELIHOOD OF A CAP. THE GREATEST SEVERE COVERAGE MAY EVOLVE OVER PORTIONS OF THE MID MS VALLEY INTO THE OH VALLEY BY DAYS 6-7.

MON MAY 7Numerical models again differ, so details of the severe threat area could change in subsequent forecasts. Scattered severe thunderstorms in IL, IN, south half OH, WV, southwest VA, northwest SC, north, central, and southwest GA, FL panhandle, east AL, east half TN, KY, east-central, southeast, and south-central MO, north and west AR, southeast OK, northeast to southwest TX in a strip from near Paris to San Angelo.

--------------------

June 7th-My First Tornado. Formerly msweather!

QUOTE

Well I don't quite trust the...

*Never Accurate Model (NAM)

or

*Even Crazier Model With Foolishness. (ECMWF)

(J/K)

Members I love:1:Joe/Chicago Storm ----->The one with the most posts...he's great!2:MissMarisia:She's a great mod!3:Jesse/WeatherMatrix:Great Moderater and blogger.If you don't mind voting for me....

...THERE IS A SLGT RISK OF SVR TSTMS FROM A PORTION OF THE NRN/CNTRL PLAINS INTO THE UPPER MS VALLEY...

...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE SERN STATES...

...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF WRN TX...

CORRECTED FOR OUTLOOK GRAPHIC

...SYNOPSIS...

UPPER TROUGH WILL TRANSITION TO A SLIGHTLY MORE AMPLIFIED REGIME BY SATURDAY WITH A TROUGH EXTENDING FROM THE NRN ROCKIES INTO THE GREAT BASIN AREA AND A DOWNSTREAM RIDGE OVER THE GREAT LAKES. A SHORTWAVE TROUGH EMANATING FROM THE SYNOPTIC SCALE TROUGH IS FORECAST TO EJECT NEWD THROUGH THE NRN PLAINS. FARTHER SOUTH A SRN STREAM IMPULSE EMBEDDED WITHIN NWLY FLOW SHOULD MOVE THROUGH A PORTION OF THE SERN STATES. ANOTHER WEAK IMPULSE MAY MOVE INTO WRN TX. AT THE SURFACE A COLD FRONT WILL MOVE SEWD THROUGH THE NRN AND CNTRL PLAINS AS SFC LOW ATTENDING THE EJECTING IMPULSE LIFTS INTO SRN MANITOBA. A QUASISTATIONARY FRONT WILL EXTEND FROM THE UPPER MS VALLEY INTO THE OH VALLEY. DRYLINE WILL PERSIST OVER THE CNTRL AND SRN HIGH PLAINS.

...NRN/CNTRL PLAINS THROUGH UPPER MS VALLEY...

A MOIST AND UNSTABLE WARM SECTOR WILL RESIDE SOUTH OF THE NW-SE ORIENTED WARM FRONT AND EAST OF THE DRYLINE AND COLD FRONT OVER THE CNTRL PLAINS. A FEW ELEVATED STORMS MAY BE ONGOING WITHIN THE ZONE OF ISENTROPIC ASCENT NORTH OF THE NW-SE ORIENTED BAROCLINIC ZONE FROM THE NRN PLAINS INTO THE UPPER MS VALLEY. THIS ACTIVITY MAY POSE SOME RISK FOR HAIL. ADDITIONAL STORMS WILL LIKELY DEVELOP DURING THE AFTERNOON FROM NEB INTO SD AS THE COLD FRONT SURGES SE IN RESPONSE TO EJECTING IMPULSE AND INTERACTS WITH THE VERY UNSTABLE WARM SECTOR. WHILE THE STRONGER WINDS ALOFT ARE EXPECTED TO REMAIN MOSTLY NORTH OF THE FRONT...SUFFICIENT FLOW WILL OVERLAP A PORTION OF WARM SECTOR TO AUGMENT VERTICAL SHEAR AND SUPPORT SUPERCELL STORMS. ACTIVITY WILL ADVANCE SEWD DURING THE EVENING AND MAY EVENTUALLY EVOLVE INTO AN MCS. LARGE HAIL AND DAMAGING WIND WILL BE THE MAIN THREATS...BUT A COUPLE TORNADOES CANNOT BE RULED OUT.

...SERN STATES...

A LOW AMPLITUDE SHORTWAVE TROUGH EMBEDDED WITHIN NWLY FLOW WILL ADVANCE THROUGH THE SERN STATES. A BELT OF 30-35 KT MID LEVEL FLOW ACCOMPANYING THIS FEATURE WILL MOVE ABOVE THE DESTABILIZING WARM SECTOR. BOUNDARY LAYER DESTABILIZATION...RESIDUAL OUTFLOW BOUNDARIES AND DEEPER FORCING FOR ASCENT ATTENDING THE IMPULSE SHOULD CONTRIBUTE TO THUNDERSTORM DEVELOPMENT DURING THE AFTERNOON WITH AN ATTENDANT THREAT OF ISOLATED DAMAGING WIND AND HAIL.

...SWRN THROUGH NCNTRL TX...

A FEW THUNDERSTORMS ARE EXPECTED TO ONCE AGAIN DEVELOP ALONG THE DRYLINE AS THE BOUNDARY LAYER DESTABILIZES...POSSIBLY AIDED BY ANOTHER SRN STREAM IMPULSE. MODERATE-STRONG INSTABILITY...STEEP LAPSE RATES AND AT LEAST MODEST VERTICAL SHEAR WILL CONTRIBUTE TO A THREAT FOR ISOLATED DAMAGING WIND AND LARGE HAIL FROM LATE AFTERNOON INTO EARLY EVENING.

...DISCUSSION... MODELS CONTINUE TO INDICATE THAT UPPER TROUGH CURRENTLY IN PROCESS OF AMPLIFYING OVER THE WRN STATES WILL MOVE THROUGH THE NRN PLAINS ON SATURDAY INTO SUNDAY. COLD FRONT ACCOMPANYING THIS FEATURE WILL CONTINUE SEWD THROUGH THE PLAINS AND MID-UPPER MS VALLEY SUNDAY /DAY 4/. SOME THREAT FOR A FEW SEVERE STORMS WILL UNDOUBTEDLY PERSIST ALONG THIS BOUNDARY AS IT INTERACTS WITH THE MODERATELY TO STRONGLY UNSTABLE WARM SECTOR...ESPECIALLY FROM THE CNTRL PLAINS INTO THE MID MS VALLEY REGION. IT APPEARS THE STRONGER WINDS ALOFT WILL REMAIN IN COOL SECTOR. DESPITE THE WEAK VERTICAL SHEAR...THE THERMODYNAMIC ENVIRONMENT WILL BE SUPPORTIVE OF SEVERE MULTICELLS THAT SHOULD ORGANIZE ALONG THE SEWD ADVANCING FRONT.

SOME SEVERE THREAT WILL PERSIST INTO MONDAY /DAY 5/ FROM THE OH VALLEY SWWD INTO THE SRN PLAINS AS THE COLD FRONT CONTINUES SEWD. BEYOND THIS TIME...PREDICTABILITY DECREASES AS DETERMINISTIC MODEL SOLUTIONS AND ENSEMBLE MEMBERS BECOME INCREASINGLY DISPERSIVE.

...SYNOPSIS... SYNOPTIC PATTERN ALOFT WILL BE CHARACTERIZED BY DEAMPLIFYING MS VALLEY RIDGING AND RELATED NET HEIGHT FALLS ACROSS MUCH OF ERN CONUS. PRIMARY SHORTWAVE TROUGH -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER INTERIOR PAC NW -- IS FCST TO MOVE EWD ACROSS NRN ROCKIES DAY-1...CONTRACTING INTO CLOSED 500-MB CYCLONE OVER MT/SK BORDER REGION BY START OF PERIOD. LOW SHOULD MOVE EWD ALONG CANADIAN BORDER TO NERN ND OR NWRN MN BY 7/12Z...WITH POSITIVELY TILTED TROUGH SWWD ACROSS WRN SD AND WY. MEANWHILE...WEAKER SHORTWAVE TROUGH WILL MOVE SLOWLY SEWD OVER COASTAL CA AND MAY DEVELOP SMALL/CLOSED 500-MB CYCLONE BY END OF PERIOD OVER OR NEAR SRN PORTIONS CA/NV. PROGS REMAIN QUITE DIFFERENT BY END OF PERIOD REGARDING AMPLITUDE/POSITION OF THIS FEATURE. WEAK/SRN-STREAM PERTURBATION...NOW EVIDENT IN VWP/PROFILER DATA AND SATELLITE IMAGERY OVER WRN AR -- IS FCST TO DRIFT SEWD OVER PORTIONS AL/GA BY 7/12Z...BECOMING PART OF BROAD/WEAK AREA OF CYCLONIC FLOW OVER NERN GULF AND FL.

AT SFC...LEE-SIDE LOW NOW OVER CENTRAL HIGH PLAINS IS FCST TO MIGRATE TO SERN SD/NWRN IA AREA BY 6/12Z...COLD FRONT EXTENDING SWWD INTO SECONDARY/FRONTAL-WAVE LOW OVER SRN KS OR NWRN OK. WAVY FRONTAL ZONE -- NOW ANALYZED FROM DELMARVA REGION TO INDIANA AND NEB -- IS EXPECTED TO MOVE SWD AS COLD FRONT ACROSS CAROLINAS TO NRN GA BY START OF PERIOD. BOUNDARY SHOULD BECOME QUASISTATIONARY NWWD OVER TN VALLEY THEN WARM FRONT ACROSS SRN/WRN IL AND IA. FRONTAL POSITION MAY BE MODULATED SOMEWHAT THROUGHOUT PERIOD BY OUTFLOW FROM CONVECTIVE COMPLEXES. BY 7/00Z...WARM FRONT SHOULD LIFT NEWD ACROSS IL AND PORTIONS LOWER OH VALLEY...WHILE COLD FRONT REACHES PORTIONS SERN KS...OK AND NW TX. EVEN BY MIDDLE OF PERIOD...MESOSCALE DISCREPANCIES ARE APPARENT IN PROGGED FRONTAL POSITIONS THAT WILL BE CRUCIAL TO GREATEST SVR PROBABILITIES.

LACK OF DEEP-LAYER SHEAR OVER MOST OF THIS CORRIDOR SUGGESTS PREDOMINANTLY MULTICELLULAR MODE...ALTHOUGH BRIEF SUPERCELL STRUCTURES ARE POSSIBLE. WARM SECTOR WILL BE CHARACTERIZED COMMONLY BY MID-UPPER 60S SFC DEW POINTS...WITH POCKETS OF 70S F...BENEATH STEEP MIDLEVEL LAPSE RATES. STG SFC DIABATIC HEATING IS EXPECTED WITH MID-LATE AFTERNOON MLCAPE 3500-5000 J/KG IN MUCH OF OUTLOOK AREA. MOST PROBABLE CORRIDOR FOR SUSTAINED/NOCTURNAL CONVECTION APPEARS TO BE NEAR WARM FRONT OVER PORTIONS INDIANA/OH...SVR POTENTIAL DIMINISHING WITH TIME AND EWD EXTENT.

GIVEN UNCERTAINTIES IN FRONTAL POSITION/TIMING AND DIFFERENCES IN AREAS OF STRONGEST LOW-LEVEL LIFT...SVR OUTLOOK IS KEPT RATHER BROAD-BRUSHED ATTM. HOWEVER...GIVEN LIKELIHOOD OF STG-EXTREME INSTABILITY ACROSS MUCH OF PREFRONTAL CORRIDOR...30% SVR CONCENTRATION EASILY MAY BECOME APPARENT WITHIN THIS AREA IN SUCCEEDING OUTLOOKS. AS IT STANDS...THREAT EXISTS FOR ISOLATED VERY LARGE/DAMAGING HAIL IN EARLY STAGES OF CONVECTIVE REGIME...ALONG WITH SVR HAIL AND GUSTS AS COVERAGE INCREASES ALONG/AHEAD OF FRONT AND COLD POOLS ACCUMULATE.

...SERN CONUS... RELATIVE CONCENTRATION OF MULTICELLULAR TSTMS...AND OF RELATED SVR POTENTIAL...IS FCST INVOF FRONT DURING AFTERNOON INTO EARLY EVENING FROM NRN FL TO SERN TN. DAMAGING GUSTS AND AT LEAST ISOLATED LARGE HAIL ARE POSSIBLE. LAPSE RATES ALOFT WILL BE RELATIVELY STEEP FOR THIS REGION...WITH STG SFC HEATING AND DEW POINTS UPPER 60S TO LOW 70S CONTRIBUTING TO 2500-3500 J/KG MLCAPE. ALTHOUGH DEEP-TROPOSPHERIC FLOW AND BULK SHEAR ARE EXPECTED TO BE VERY WEAK...POTENTIAL EXISTS FOR TSTMS TO BUILD INTO FORWARD-PROPAGATING COMPLEX WITH ACCORDINGLY ENHANCED WIND THREAT MOVING SWD ACROSS THIS CORRIDOR.

...SYNOPSIS... PROGRESSIVE MID-UPPER LEVEL PATTERN IS EXPECTED DAY-3...FEATURING SHORTWAVE TROUGH NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER INTERIOR PAC NW. BY START OF PERIOD...ASSOCIATED 500-MB LOW SHOULD BE MOVING EWD ALONG CANADIAN BORDER INVOF NERN ND/NWRN MN...WITH TROUGH SWWD ACROSS WY. THIS LOW SHOULD MOVE EWD ACROSS LS OR ADJOINING PARTS OF NWRN ONT THROUGH PERIOD. RELATED SFC FRONTAL-WAVE CYCLONE SHOULD CURVE EWD TO NEWD FROM IL OR INDIANA ACROSS UPPER OH VALLEY/LOWER GREAT LAKES REGION. TRAILING COLD FRONT SHOULD MOVE SEWD ACROSS LOWER OH VALLEY AND ARKLATEX REGION DURING FIRST HALF OF PERIOD..THEN REACHING UPPER OH VALLEY...CENTRAL APPALACHIANS...MID-SOUTH AND CENTRAL/SRN TX BY 8/12Z. TX PORTION OF FRONT MAY STALL BY THEN. AS WITH DAY-2...THERE IS CONSIDERABLE UNCERTAINTY REGARDING TIMING/POSITION OF COLD FRONT DURING AFTERNOON...CORRESPONDING TO PERIOD OF MOST PROBABLE CONVECTIVE INITIATION IN BOTH NEAR-FRONTAL REGIMES DISCUSSED BELOW.

...SW TX...LOWER PECOS VALLEY REGION... STG DIURNAL HEATING...ALONG WITH MOISTURE TRANSPORT...STEEP MIDLEVEL LAPSE RATES AND FRONTAL ASCENT...MAY BE SUFFICIENT TO SUPPORT TSTMS OVER PARTS OF THIS REGION. LARGE HAIL AND DAMAGING GUSTS WOULD BE POSSIBLE. LOW-LEVEL WAA AND MOIST ADVECTION SHOULD SPREAD NWWD OVER MORE OF SW TX AND SERN NM AFTER 8/00Z...POTENTIALLY SUPPORTING ADDITIONAL DEVELOPMENT OVER THOSE AREAS. MOST FCST SCENARIOS OF SERN CONUS LOW POSITION ALSO WOULD SUPPORT STRONG UPPER-LEVEL DIFLUENCE OVER THIS CORRIDOR...WITH SWATH OF LARGE-SCALE LIFT BENEATH LEFT-EXIT REGION OF GENTLY CYCLONICALLY CURVED SUBTROPICAL JET BRANCH. ADDITIONAL TSTMS SHOULD DEVELOP DIURNALLY INTO EARLY EVENING OVER NEARBY MOUNTAINS OF NRN MEX...HOWEVER WIND PROFILES IN MOST FCST SOUNDINGS SUGGEST ANY SUCH CONVECTION WILL MOVE SLOWLY SEWD AND REMAIN OVER MEX.

...SERN CONUS... AL/GA FRONTAL ZONE DISCUSSED IN DAY-2 OUTLOOK SHOULD BECOME QUASISTATIONARY THIS PERIOD...BENEATH RESIDUAL MID-UPPER TROUGHING...PROVIDING SUPPORT FOR CONVECTIVE POTENTIAL IN THAT REGION. SEA BREEZE AND OUTFLOW BOUNDARIES WILL MORE PRECISELY FOCUS CONVECTION ON MESOSCALE. WEAK DEEP-LAYER WINDS AND SHEAR SHOULD KEEP TSTMS MULTICELLULAR IN NATURE...BUT BUOYANCY SHOULD BE FAVORABLE FOR AT LEAST ISOLATED DAMAGING GUSTS AND LARGE HAIL. MORE DENSE LOCAL CONCENTRATIONS ALSO ARE POSSIBLE...BUT THAT MESOSCALE DEPENDENCY PRECLUDES SPECIFIC CATEGORICAL AREA ATTM.

...DISCUSSION... MID-UPPER CYCLONE NEAR CANADIAN BORDER...DESCRIBED IN DAY-2/DAY-3 OUTLOOKS...SHOULD MOVE EWD ACROSS PORTIONS ONT TOWARD SWRN QUE DAY-4/8TH-9TH. DISCREPANCIES AMONG GUIDANCE GET FAIRLY LARGE BY THIS TIME REGARDING TIMING/AMPLITUDE OF THIS SYSTEM AND RELATED TROUGHING SWD ACROSS ERN CONUS. WHILE SOME SVR IS EXPECTED ALONG/AHEAD OF RELATED SFC COLD FRONT...MOST PROBABLY OVER CENTRAL APPALACHIANS TO TN VALLEY/MID-SOUTH REGION DAY-4...TOO MUCH UNCERTAINTY EXISTS REGARDING CONCENTRATION OF ACTIVITY AND FRONTAL CHARACTERISTICS TO WARRANT AOA 30% UNCONDITIONAL SVR AREA ATTM.

MEANWHILE...AT LEAST ISOLATED SVR MAY OCCUR FROM RIO GRANDE AREA OF SW TX TO PECOS VALLEY OR ERN NM DAYS 4-6/8TH-11TH...AS PREVIOUSLY CUT-OFF LOW BECOMES PROGRESSIVE AGAIN. NRN-STREAM PERTURBATION SHOULD CROSS PAC NW AND NRN ROCKIES DAYS 4-6...POTENTIALLY YIELDING SOME SVR THREAT OVER NRN PLAINS DAY-6/10TH-11TH. WHILE DEEP-LAYER SHEAR WILL BE FAVORABLE AHEAD OF THAT TROUGH...LOW-LEVEL MOISTURE RETURN MAY BE WEAK BASED ON MREF/ECMWF GUIDANCE.

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE UPPER MIDWEST...OZARKS...MID MS VALLEY...SRN PLAINS...CNTRL PLAINS...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE ERN GULF COAST STATES...

...MID TO UPPER MS VALLEY... AN UPPER-LEVEL RIDGE WILL BE IN PLACE SUNDAY FROM THE MID-MS VALLEY NWD INTO THE GREAT LAKES REGION. AT THE SFC...A COLD FRONT WILL MOVE SEWD ACROSS THE UPPER MIDWEST WITH A BROAD WARM SECTOR IN PLACE AHEAD OF THE FRONT FROM THE UPPER MS VALLEY EXTENDING SWWD ACROSS THE OZARKS. AN MCS MAY BE ONGOING NEAR THE FRONT ACROSS PARTS OF THE REGION SUNDAY MORNING AND OUTFLOW BOUNDARIES ASSOCIATED WITH THE MCS SHOULD FAVOR CERTAIN AREAS FOR CONVECTIVE INITIATION. AS SFC TEMPS WARM...NEW CONVECTION SHOULD INITIATE NEAR THOSE BOUNDARIES WHERE THE AIRMASS HAS BEEN UNDISTURBED. AS STORMS INCREASE IN COVERAGE...MCS DEVELOPMENT WILL BE POSSIBLE ACROSS THE REGION LATE SUNDAY AFTERNOON WITH STORMS MOVING SEWD ACROSS THE SLIGHT RISK AREA.

FORECAST SOUNDINGS ACROSS THE WARM SECTOR IN CNTRL IA...NRN IL AND NRN MO BY EARLY AFTERNOON HAVE MODERATE INSTABILITY...MLCAPE IN THE 2500 TO 3500 J/KG RANGE WITH 0-6 KM SHEAR OF 30 TO 40 KT. THIS ENVIRONMENT SHOULD SUPPORT SUPERCELLS AND A THREAT FOR LARGE HAIL SHOULD EXIST WHERE SUPERCELLS HAVE ACCESS TO STRONG INSTABILITY. SUPERCELLS SHOULD ALSO HAVE AN ISOLATED TORNADO THREAT. HOWEVER...FORECAST WIND PROFILES SUGGEST THE DOMINANT STORM MODE IS QUESTIONABLE. AS WINDS VEER AT LOW-LEVELS AHEAD OF THE APPROACHING FRONT...LINEAR MULTICELLS MAY DEVELOP WITH A WIND DAMAGE POTENTIAL. DURING THE LATE AFTERNOON AND EARLY EVENING...A NARROW CORRIDOR WITH AN ENHANCED SEVERE THREAT COULD EXIST FROM SRN WI SWWD ACROSS NW IL INTO ERN IA...NRN MO AND FAR ERN KS WHERE THE COMBINATION OF INSTABILITY/DEEP LAYER SHEAR SHOULD BE MAXIMIZED AND CO-LOCATED WITH STEEP LAPSE RATES.

...CNTRL AND SRN PLAINS... AN AXIS OF STRONG INSTABILITY IS FORECAST ACROSS THE SRN PLAINS SUNDAY AFTERNOON WITH THE MODELS DEVELOPING ISOLATED TO SCATTERED THUNDERSTORMS AHEAD OF A SEWD MOVING COLD FRONT. THE THERMODYNAMIC ENVIRONMENT WILL BE FAVORABLE FOR SEVERE STORMS. FORECAST SOUNDINGS FROM SE KS SWWD ACROSS CNTRL OK SHOW MLCAPE VALUES OF 4000 TO 5000 J/KG WITH LAPSE RATES AROUND 8.0 C/KM. ALTHOUGH DEEP LAYER SHEAR IS ONLY FORECAST TO BE AROUND 20 KT...THE STRONG INSTABILITY SHOULD COMPENSATE...MAKING SUPERCELL DEVELOPMENT POSSIBLE ACROSS THE REGION. LARGE HAIL MAY BE THE GREATEST THREAT ALTHOUGH ANY SUPERCELL THAT DEVELOPS SHOULD ALSO HAVE A WIND DAMAGE POTENTIAL. AN ISOLATED TORNADO OR TWO CAN NOT BE RULED OUT. THE SEVERE THREAT SHOULD BE MORE ISOLATED WITH SSWWD EXTENT IN THE SRN PLAINS DUE TO THE WEAKER INSTABILITY FORECAST ALONG THE DRYLINE WCNTRL TX.

...ERN GULF COAST STATES... A BROAD WARM SECTOR IS FORECAST ACROSS THE GULF COAST STATES SUNDAY WHERE THE MODELS DEVELOP SCATTERED THUNDERSTORMS BY EARLY AFTERNOON. FORECAST SOUNDINGS SHOW THE STRONGEST INSTABILITY FROM ERN AL SEWD ACROSS SRN GA WITH MLCAPE IN THE 3000 TO 4000 J/KG RANGE. THIS COMBINED WITH STEEP LOW-LEVEL LAPSE RATES MAY BE FAVORABLE FOR ISOLATED DAMAGING WIND GUSTS WITH THE MORE INTENSE PULSE STORMS SUNDAY AFTERNOON.

Im guessing it's going to be just as hard to forecast as the past several days. It's going to depend on where the convective remnants from tonight go. They were counting on the IA cluster last night diving SE and it never happened. I see it as we're in a 15% risk so we're also in an 85% chance of no risk. Although we have to be approaching one of the 15 in 100 times it happens. Thinking I can recall about 80 times it hasn't. 3rd times a charm, right?

Im guessing it's going to be just as hard to forecast as the past several days. It's going to depend on where the convective remnants from tonight go. They were counting on the IA cluster last night diving SE and it never happened. I see it as we're in a 15% risk so we're also in an 85% chance of no risk. Although we have to be approaching one of the 15 in 100 times it happens. Thinking I can recall about 80 times it hasn't. 3rd times a charm, right?

SUMMARY...ISOLATED DRYLINE THUNDERSTORMS MAY BEGIN TO DEVELOP OVER THE NEXT HOUR OR TWO OVER CNTRL TX...PROGRESSING EWD WITH TIME. A WW MAY NEED TO BE ISSUED. LARGE HAIL AND DMGG WINDS WILL BE THE PRIMARY THREATS.

DISCUSSION...2130Z VISIBLE IMAGERY REFLECTS AN INCREASING CU FIELD ALONG THE DRYLINE...PARTICULARLY EAST OF SJT WHERE RADAR REFLECTIVITY IS BEGINNING TO INCREASE IN CONCHO COUNTY. HOWEVER...NO NOTABLE UPPER FEATURE IS EVIDENT THAT WOULD PROVIDE FORCING FOR ASCENT...WITH WV IMAGERY AND PROFILER DATA GENERALLY IMPLYING ANTICYCLONIC FLOW ALOFT...POSSIBLY SUPPRESSING MORE WIDESPREAD POTENTIAL FOR THUNDERSTORM DEVELOPMENT. REGARDLESS...SFCOA INDICATES NO CONVECTIVE INHIBITION REMAINING. CONVERGENCE ALONG THE DRYLINE AND EXTREME INSTABILITY MAY BE SUFFICIENT TO OVERCOME SOMEWHAT HOSTILE CONDITIONS ALOFT. VIGOROUS UPDRAFTS CAN BE EXPECTED IN STORMS THAT CAN BECOME SUSTAINED...WITH LARGE HAIL AND DMGG WINDS LIKELY. BRIEF SUPERCELLULAR STRUCTURES MAY BE POSSIBLE GIVEN VERY SUBTLE LOW-MID LEVEL VEERING...THOUGH GENERALLY WEAK FLOW ALOFT SHOULD LIMIT GREATER ORGANIZATION.

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID MS VLY SSW INTO PARTS OF THE SRN PLNS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE SERN STATES...

...SYNOPSIS... SRN SK UPR LOW EXPECTED TO TRACK SLOWLY E INTO SRN MB THIS PERIOD AS TRAILING...POSITIVE TILT TROUGH EDGES MORE SLOWLY E ACROSS THE GRT BASIN. THE EWD ADVANCE OF THE LOW/TROUGH...AND THAT OF WEAKER DISTURBANCES TO THEIR E...WILL SERVE TO DEPRESS HEIGHTS FROM THE N CNTRL STATES INTO THE UPR GRT LKS. LESSER HEIGHT FALLS WILL PREVAIL OVER THE SRN PLNS AND OVER THE TN VLY/GULF CST STATES IN CONJUNCTION WITH RESPECTIVE SRN BRANCH DISTURBANCES MOVING NEWD FROM NM AND SEWD INTO MS/AL.

AT LWR LVLS...SSW-NNE COLD FRONT ASSOCIATED WITH MB/GRT BASIN SYSTEM WILL ADVANCE E/SE FROM THE LWR MO VLY/CNTRL PLNS THIS MORNING INTO THE MID MS VLY/SRN PLNS BY EVE. THE SRN PART OF THE FRONT WILL OVERTAKE THE DRYLINE IN WRN OK...WITH THE DRYLINE CONTINUING S/SW FROM THERE ACROSS WRN PARTS OF THE TX HILL COUNTRY TO THE TX BIG BEND. FARTHER NE...FRONT ATTM EXTENDING FROM CNTRL IA TO SRN IND EXPECTED TO ADVANCE SLOWLY NEWD TODAY...WITH MOVEMENT IN IA LIKELY OFFSET BY OUTFLOW FROM ONGOING TSTMS.

WHILE LARGE SCALE FORCING FOR ASCENT WILL REMAIN WEAK...SFC HEATING OF SEASONABLY MOIST/BUOYANT AIR ALONG AND AHEAD OF COLD FRONT/DRYLINE...AND ALONG WARM FRONT...WILL YIELD A FAIRLY LARGE AREA SUBJECT TO A CONDITIONAL THREAT FOR SVR TSTMS.

...MID MS VLY SSW INTO PARTS OF THE SRN PLNS TODAY/TNGT... CNTRL/SW IA SQLN EXPECTED TO CONTINUE SLOWLY E/SE THROUGH THIS MORNING. WHILE STRONGER STORMS WITHIN THIS BAND REMAINED ISOLD THROUGH THE OVERNIGHT...UPDRAFTS MAY INTENSIFY/BECOME SUSTAINED LATER THIS MORNING AS SFC HEATING DESTABILIZES INFLOW. ALTHOUGH FCST WIND PROFILES AND THE ORIENTATION OF THE CONVECTIVE SYSTEM RELATIVE TO MEAN SW TO WSWLY MID LVL FLOW DO NOT APPEAR OPTIMAL FOR INTENSE DEVELOPMENT...SUFFICIENT SHEAR AND INSTABILITY LIKELY WILL EXIST FOR EMBEDDED STORMS WITH SVR WIND/HAIL. A FEW STORMS MAY FORM AHEAD OF THE MCS INVOF DIFFUSE WARM/STNRY FRONT IN IL. THESE MAY YIELD SVR HAIL AND...POSSIBLY...A WEAK TORNADO OR TWO GIVEN MOIST/BACKED LOW LVL FLOW.

ADDITIONAL TSTMS/STORM CLUSTERS SHOULD FORM THIS AFTN ALONG COLD FRONT AND RESIDUAL OUTFLOW BOUNDARIES FROM NW MO/NE KS SSW INTO OK. A BIT LATER IN THE DAY...STORMS ALSO MAY FORM ALONG THE DRYLINE IN TX. STRONG WARM SECTOR INSTABILITY /SBCAPE TO 4000 J PER KG/ SUGGESTS THE POSSIBILITY FOR SVR HAIL AND WIND. HOWEVER...MODEST /20-30 KT/ DEEP SWLY SHEAR SHOULD LIMIT UPDRAFT SUSTENANCE/ ORGANIZATION...WITH COMPLEX STORM MODES/SLOWLY-MOVING MULTICELL CLUSTERS...AND MARGINAL/TRANSIENT SUPERCELLS EXPECTED. CORRIDORS OF GREATEST SVR RISK WILL BE DETERMINED BY STORM-SCALE INTERACTIONS GIVEN ABSENCE OF STRONG SHEAR.

LOOSELY-ORGANIZED BANDS/CLUSTERS OF STORMS MAY PERSIST INTO TNGT E/SE INTO PARTS OF IL...IND...MO...AND AR...BUT WITH A GRADUALLY DIMINISHING/MORE EPISODIC SVR THREAT.

...SERN STATES TODAY... SMALL...LOOSELY-ORGANIZED MCS NOW IN NRN AL HAS EVOLVED FROM SIMILAR OVERNIGHT ACTIVITY THAT EXTENDING UPSTREAM INTO WRN TN. STORMS SHOULD INCREASE IN COVERAGE AND POSSIBLY STRENGTH TODAY IN RESPONSE TO STRONG SFC HEATING AND WEAK ASCENT ASSOCIATED WITH AFOREMENTIONED UPR IMPULSE. WIND FIELD WILL REMAIN WEAK. BUT MODEST MEAN NNWLY FLOW PARALLEL TO SYSTEM OUTFLOW BOUNDARY...PRESENCE OF EML...AND HIGH PWS SUGGEST THE POSSIBILITY FOR STORMS TO ORGANIZE INTO FORWARD-PROPAGATING BANDS BY AFTN...WITH AN ACCOMPANYING RISK FOR DMG WIND/MARGINALLY SVR HAIL.